1. Even if we cut government spending a lot, some taxes will have to go up. This seems like the least bad tax to raise or create, since it has some chance of producing a better outcome. It’s hard to say that about most of the other potential tax boosts. I’d also cut the tax deduction for mortgage interest, of course. That too could improve the quality of outcomes.
3. A carbon tax might lead to a new green technology, with high upfront costs and low marginal costs. Some of the rest of the world might then adopt the technology, even if those countries don’t ever adopt a carbon tax. In the short run this seems a little pie-in-the-sky, but in the longer run is it so crazy? Haven’t the Chinese adopted most of our other technological innovations?